Thermal electric fire-alarm.



4 PATENTED MAY 5, 1903 T. B. & P. A. DUNCAN.

THERMAL ELECTRIC FIRE ALARM.

' no MODEL.

APPLICATION FILED MAR. 6, 1902.

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UNITED STATES Patented May 5, 1903.

PATE T OFFICE.

THOMAS E. DUNCAN AND FRANCIS A. DUNCAN, OF NEWBERG, OREGON.

THERMAL ELECTRIC FIRE-ALARM.

SEEOIFICATION forming part of Letters Patent N0. 727,315, dated. May 5, 1903.

Application filed March 6, 1302x Serial No. 96,918. (No model.)

To all whom it may concern:

Be it known that we, THOMAS E. DUNCAN and FRANCIS A. DUNCAN, citizens of the United States, residing at Newberg, in the county of Yamhill and State of Oregon, have invented a certain new and useful Thermal Electric Fire-Alarm, of which the following is a specification, reference being bad therein to the accompanying drawings. This invention relates to thermal electric fire-alarms, the object in view being to provide a simple and reliable apparatus which operates automatically under the influence of an excessive degree of heat to close an electric circuit in which one or more alarmbells may be arranged and located at different and, if desired, dist-ant points, thereby notifying one or more persons of a conflagration. The apparatus is so constructed and arranged that upon a fire breaking out in any room of a dwelling, public or private, notice will be given as to the particular room in which the fire has started. If so desired, an

alarm may be sounded at a point distant from the house, as in a fire-alarm station or police-station.

With the above general objects in view the invention consists in the novel construction, combination, and arrangement hereinafter fully described, illustrated, and claimed.

- In the accompanying drawings, Figure 1 is a front elevation of a thermal circuit-closer constructed in accordance with the present invention. Fig. 2 is a central vertical detail section through the thermic cell, its neck, and the supporting-bar and clamp. Fig. 3 is a cross horizontal section taken through the bottom crossbar and clamp.

Like reference charactersdenote like parts in all the figures of the drawings.

Referring to the drawings, 1 designates a suitable supporting-base, which may, if desired, be in the form of a board provided with a suitable opening 2 to receive and permit of the expansive action of the thermic cell 3. The lower portion of the supporting-base is crossed by a bar 4, to which the neck 5 of the thermic cell is fastened by means of a clamp G. The cross-bar 4, which is preferably constructed of brass, is offset from the front of the base, as shown at 7, to provide room for the thermic cell and hold the same away from the wall or other support against which the base 1 is fastened. Centrally the cross-bar 4 is provided with a semicylindrical socket 8 to receive the neck 5 of the cell 3, while the clamp 6 is in the form of a metal strap, the central portion of which is provided with a 'semicylindrical socket 9, which fits closely around the neck 5 for securely holding the latter.

The clamp 6 is provided with longitudinal slots 10 to admit of the passage of the fiattened heads of thumb-operated clampingscrews 11, so that by turning the heads of said screws to register with the slots the clamp 6 may be detached instantly, thus permitting the thermic cell to be removed whenever it is necessary to refill the same. Vertical movement of the neck 5 is prevented by shoulderingsaid neck, as shown at 12, above and beneath the cross-bar 4.

13 designates a screw-plu g, which is threaded into the lower end of the hollow neck5 and screws up against a packing washer 14 within the neck, as shown at Fig. 2, thus forming a liquid and air tight joint, which prevents the escape and evaporation of the fluid in the thermic cell.

The thermic cell 3 is formed of two thin disks or diaphragms 15, of metal, and joined at their edges or peripheries, as at 16, and are preferably formed with concentric corrugations 17 to facilitate the expansion of the cell under the action of heat. A suitable volatile liquid is primarily introduced into the thermic" cell and serves when subjected to excessive heat to expand the cell. As the cell is rigidly held at the bottom by the neck 5, any movement or expansion thereof must take place in an upward direction. Therefore the contact-post 18 is connected permanently and centrally to the upper disk or diaphragm 15, said post terminating at its upper extremity in a contact-point 19, which is of course movable up and down under the influence of the thermic cell. Near its up per end the post 18 passes through a suitable guide 20, which prevents lateral variation of the contact-point.

Arranged immediately opposite the contact-point 19 and in the path of movement of said contact-point is a combined contact-1ever and indicator 21, fulcrumed at 22 on the supporting base and provided at one end with a pointer 23, adapted to traverse a thermometric scale 24, also secured to the base. 25 designates a bracket also secured to the base and preferably of metal, so as to form a conductor for the electric current. The bracket 25 has a projecting portion 26 with a threaded opening, through which passes a regulating device, preferably in the form of ascrew 27, the lower end of which normally impinges against the lever 21. By turning the screw 27 the point 23 of the lever 21 maybe adjusted to any graduation of the scale 2A for the purpose of primarily setting the apparatus so that electrical contact will be made between the point 19 and the lever 21 at any predetermined degree of temperature. The position of adjustment of the regulating-screw 27 is fixed by means of a lock or jam nut 28.

The bracket 25 carries one of the bindingposts 29, to which is connected one of the circuit-wires h. A combined lever-restoring spring and flexible electrical conductor 30 is interposed between one end of the lever 21 and the bracket 26 or binding-post 29, so that when the lever is moved out of electrical contact With the regulator 27 the continuity of the circuit will be still maintained through the connection 30. The other circuit-wire, b, connects directly with the contact-post 18, preferably by means of a binding-post 31.

The thermal circuit-closer (illustrated in Fig. 1) when influenced by excessive heat causes the contact-point 19 to move until it comes in contact with the lever 21, Wherenpon the circuit is closed, the current passing through wire I) to post 18, contact-point l9, lever 21, regulator 27, bracket 26, binding-post 29, and remaining circuit-wire h. As the thermic cell continues to expand the point 19 moves the lever out of contact with the regulating screw 27. This, however, does not break the circuit, the latter then passing from the lever 21 through the connection 30 to the bracket 26, binding-post 29, and Wire 71.

The apparatus is entirely automatic in operation and constitutes reliable means for indicating in a main ofice the particular room or locality Where the fire starts, it being intended to place one of the thermostats in each room, as Well as in the corridors and at other desirable points.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is-

1. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, both the contact point and lever being included in an electric circuit, and a regulating device associated with the contactlever also included in the circuit.

2. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, both the contact point and lever beingincluded in an electric circuit, and a regulating-screw for adjusting the contact-lever, said screw being arranged in the circuit.

3. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, both the contact point and lever being included in an electric circuit, a regulating-screw associated with the lever, and a flexible conductor connected with the lever, the regulating-screw being only primarily in the circuit and the flexible conductor constantly in the circuit, substantially as described.

ei. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, the contact point and lever being included in an electric circuit, a regulatingscrew associated with the contact-lever, and a combined spring and electric conductor associated with the lever and also arranged in the circuit.

5. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, the contact point and lever being included in an electric circuit, a thermometric scale associated with the contact lever and indicator, and a lever-regulating device also included in the circuit.

6. In a thermal electric alarm, the combination of a thermic cell, a contact-point mow able therewith, a combined contact lever and indicator arranged in the path of said contact-point, the contact point and lever being included in an electric circuit, a metal bracket carrying one of the binding-posts in the circuit, a metallic regulator for the contact-lever mounted on said bracket, and a flexible electrical conductor interposed between the contact-lever and bracket.

7. In a thermal electric alarm, the combination of a thermic cell, a contact-point movable therewith, a combined contact lever and indicator arranged in the path of said contact-point, the contact point and lever being included in an electric circuit, a supportingbase for said parts, and a clamp arranged to permit the thermic cell to be detached from the supporting-base for the purpose specified.

In testimony whereof we affix our signatures in presence of two witnesses.

THOMAS B. DUNCAN. FRANCIS A. DUNCAN.

Witnesses:

LULU L. NIGHT, A. P. OLIVER. 

